Tuesday, 22 May 2012

Hinterland Who's Who: The Asian Snakehead Fish.

The snakehead, a predatory fish, was spotted last week for the first time in British Columbia, at an urban park. Since its first appearance in the United States nearly a decade ago, the fish has caused major destruction of marine ecosystems.{...}

Rod Gonzalez was out at Central Park in Burnaby on May 13, feeding the koi fish in one of the park’s ponds, when he spotted a large fish.

“At first I didn’t know what it was but as the camera zoomed in, I realized it was a snakehead,” said Gonzalez, who posted the video he shot on B.C. Aquaria.com, a forum for fish hobbyists. “I’ve seen it online and on shows but never seen one in real life.”{...}

The snakehead would most likely be a northern snakehead, native to Asia, and available for purchase in Vancouver as food. Gonzalez said he’s known people who kept the fish as pets, and has heard that when they get too big, the fish is dumped.

Snakeheads can grow as long as 1.2 metres and weigh as much as seven kilograms. B.C. is considering a ban on their sale.{...}

“The big concern is if it’s a northern snakehead that it may get in the Fraser River and then it would be a predatory fish that some of our native fish wouldn’t know how to respond to,” said Herbourg. “It would be another stressor in the ecosystem for our fish species, and it’s hard to predict outcomes.”

Snakeheads in B.C.’s rivers could affect migrating salmon, according to Herbourg, just as the fish’s appearance in Maryland waters hurt the existing largemouth bass population.

Professor Jonathan Moore at Simon Fraser University, who specializes in conservation and ecology of aquatic systems, said the most likely way the snakehead found its way into the Burnaby pond was through someone leaving it there.{...}

Not only could native salmon species be harmed if the snakehead population grows, but other species like amphibians could be decimated by an invasive fish like the snakehead which is known for its hardy survival skills and can eat other fish up to a third of their body length.

The abilities of snakeheads to survive and push out existing species in marine eco-systems have taken on almost mythical proportions. But Herbourg notes that tales of the fish being able to walk on land or even tear off someone’s arm are fictional.

There's probably a metaphor for immigration in here somewhere but I haven't put my finger on it yet.